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grid.cc
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Wed, Jun 19, 18:06

grid.cc
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#include "grid.hh"
#include <QDebug>
#include <mpi.h>
typedef enum {
_north,
_south,
_east,
_west,
_north_east,
_north_west,
_south_east,
_south_west
} comm_tag_t;
Grid::~Grid() {
delete[] _grid;
MPI_Type_free(&_column_t);
MPI_Type_free(&_line_t);
MPI_Type_free(&_corner_t);
MPI_Request * req = _requests;
for (int i = 0; i < 8 * 2; ++i, ++req) {
MPI_Request_free(req);
}
delete[] _requests;
}
void Grid::initalizeCommunicationRequests(MPI_Comm & comm, int coords[2]) {
_nb_requests = 8;
_requests = new MPI_Request[_nb_requests * 2];
MPI_Type_vector(_dims[0], _ghosts, _dims[1] + 2 * _ghosts, MPI_CHAR,
&_column_t);
MPI_Type_vector(_ghosts, _dims[1], 2 * _ghosts, MPI_CHAR, &_line_t);
MPI_Type_vector(_ghosts, _ghosts, _dims[1] + 2 * _ghosts, MPI_CHAR,
&_corner_t);
MPI_Type_commit(&_column_t);
MPI_Type_commit(&_line_t);
MPI_Type_commit(&_corner_t);
int prank;
MPI_Comm_rank(comm, &prank);
auto data_addr = [this](int i, int j) -> char * {
if (i < 0) {
i = _dims[0] + 2 * _ghosts + i;
}
if (j < 0) {
j = _dims[1] + 2 * _ghosts + j;
}
return _grid + i * (_dims[1] + 2 * _ghosts) + j;
};
MPI_Request * srequests = _requests;
MPI_Request * rrequests = _requests + _nb_requests;
{ /* south east -> north west */
int nrank;
int rcoords[2] = {coords[0] - 1, coords[1] - 1};
MPI_Cart_rank(comm, rcoords, &nrank);
char * send = data_addr(_ghosts, _ghosts);
char * recv = data_addr(0, 0);
MPI_Send_init(send, 1, _corner_t, nrank, _south_east, comm, srequests);
MPI_Recv_init(recv, 1, _corner_t, nrank, _north_west, comm, rrequests);
++srequests;
++rrequests;
}
{ /* south west -> north east */
int nrank;
int rcoords[2] = {coords[0] - 1, coords[1] + 1};
MPI_Cart_rank(comm, rcoords, &nrank);
char * send = data_addr(_ghosts, -2 * _ghosts);
char * recv = data_addr(0, -_ghosts);
MPI_Send_init(send, 1, _corner_t, nrank, _south_west, comm, srequests);
MPI_Recv_init(recv, 1, _corner_t, nrank, _north_east, comm, rrequests);
++srequests;
++rrequests;
}
{ /* north west -> south east */
int nrank;
int rcoords[2] = {coords[0] + 1, coords[1] + 1};
MPI_Cart_rank(comm, rcoords, &nrank);
char * send = data_addr(-2 * _ghosts, -2 * _ghosts);
char * recv = data_addr(-_ghosts, -_ghosts);
MPI_Send_init(send, 1, _corner_t, nrank, _north_west, comm, srequests);
MPI_Recv_init(recv, 1, _corner_t, nrank, _south_east, comm, rrequests);
++srequests;
++rrequests;
}
{ /* north_east -> south_west */
int nrank;
int rcoords[2] = {coords[0] + 1, coords[1] - 1};
MPI_Cart_rank(comm, rcoords, &nrank);
char * send = data_addr(-2 * _ghosts, _ghosts);
char * recv = data_addr(-_ghosts, 0);
MPI_Send_init(send, 1, _corner_t, nrank, _north_east, comm, srequests);
MPI_Recv_init(recv, 1, _corner_t, nrank, _south_west, comm, rrequests);
++srequests;
++rrequests;
}
// Sides
{ /* south -> north */
int nrank;
int rcoords[2] = {coords[0] - 1, coords[1]};
MPI_Cart_rank(comm, rcoords, &nrank);
char * send = data_addr(_ghosts, _ghosts);
char * recv = data_addr(0, _ghosts);
MPI_Send_init(send, 1, _line_t, nrank, _north, comm, srequests);
MPI_Recv_init(recv, 1, _line_t, nrank, _south, comm, rrequests);
++srequests;
++rrequests;
}
{ /* west -> east */
int nrank;
int rcoords[2] = {coords[0], coords[1] + 1};
MPI_Cart_rank(comm, rcoords, &nrank);
char * send = data_addr(_ghosts, -2 * _ghosts);
char * recv = data_addr(_ghosts, -_ghosts);
MPI_Send_init(send, 1, _column_t, nrank, _west, comm, srequests);
MPI_Recv_init(recv, 1, _column_t, nrank, _east, comm, rrequests);
++srequests;
++rrequests;
}
{ /* north -> south */
int nrank;
int rcoords[2] = {coords[0] + 1, coords[1]};
MPI_Cart_rank(comm, rcoords, &nrank);
char * send = data_addr(-2 * _ghosts, _ghosts);
char * recv = data_addr(- _ghosts, _ghosts);
MPI_Send_init(send, 1, _line_t, nrank, _south, comm, srequests);
MPI_Recv_init(recv, 1, _line_t, nrank, _north, comm, rrequests);
++srequests;
++rrequests;
}
{ /* east -> west */
int nrank;
int rcoords[2] = {coords[0], coords[1] - 1};
MPI_Cart_rank(comm, rcoords, &nrank);
char * send = data_addr(_ghosts, _ghosts);
char * recv = data_addr(_ghosts, 0);
MPI_Send_init(send, 1, _column_t, nrank, _east, comm, srequests);
MPI_Recv_init(recv, 1, _column_t, nrank, _west, comm, rrequests);
++srequests;
++rrequests;
}
}

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